<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  </head>
  <body>
    <script>
      let arr = new Array('baidu', 'yahoo', 'tom', 'google', 'tom')
      // console.log(arr)
      // let hd = [12, 34, 34]
      // console.log(hd)

      //   console.log(arr.length)

      //   arr.push(4)
      //   arr.unshift('sina')
      //   //   console.log(arr)
      //   arr[100] = 'facebook'
      //   arr.pop()
      //   arr.shift()
      //   console.table(arr)

      //   arr[arr.length] = 'taobao'

      //   console.log(arr.lastIndexOf('tom'))

      //   if ([]) console.log('为真')

      console.log(arr.includes('tom'))
    </script>
  </body>
</html>
